Crown CTs 4200USP/CN User manual

Operation Manual
Obtaining Other Language Versions: To obtain information in another language about the use of this product, please contact your
local Crown Distributor. If you need assistance locating your local distributor, please contact Crown at 574-294-8000.
This manual does not include all of the details of design, production, or variations of the equipment. Nor does it cover every possible
situation which may arise during installation, operation or maintenance.
The information provided in this manual was deemed accurate as of the publication date. However, updates to this information may have
occurred. To obtain the latest version of this manual, please visit the Crown website at www.crownaudio.com.
Trademark Notice: Crown, Crown Audio, Amcron, Com-Tech, IQ System, and Multi-Mode are registered trademarks of Crown
International. HiQnet and System Architect are trademarks of Harman Pro Group. Other trademarks are the property of their respective
owners.
Some models may be exported under the name Amcron.®
©2008 by Crown Audio®Inc., 1718 W. Mishawaka Rd., Elkhart, Indiana 46517-9439 U.S.A. Telephone: [phone]
139309-4
9/08
CTs Multi-Channel USP/CN Series
CTs 8200USP/CN
CTs 4200USP/CN

Operation Manual
CTs Multi-Channel Power Amplifiers
page 2
1. Read these instructions.
2. Keep these instructions.
3. Heed all warnings.
4. Follow all instructions.
5. Do not use this apparatus near water.
6. Clean only with a dry cloth.
7. Do not block any ventilation openings. Install in accordance
with the manufacturer’s instructions.
8. Do not install near any heat sources such as radiators, heat
registers, stoves, or other apparatus (including amplifiers)
that produce heat.
9. Do not defeat the safety purpose of the polarized or
grounding-type plug. A polarized plug has two blades with
one wider than the other. A grounding-type plug has two
blades and a third grounding prong. The wide blade or
the third prong is provided for your safety. If the provided
plug does not fit into your outlet, consult an electrician for
replacement of the obsolete outlet.
Important Safety Instructions
MAGNETIC FIELD
CAUTION! Do not locate sensitive high-gain equipment such as pre-
amplifiers directly above or below the unit. Because this amplifier has a
high power density, it has a strong magnetic field which can induce hum
into unshielded devices that are located nearby. The field is strongest
just above and below the unit.
If an equipment rack is used, we recommend locating the amplifier(s)
in the bottom of the rack and the preamplifier or other sensitive equip-
ment at the top.
The lightning bolt triangle is used to alert the user to the risk of
electric shock.
The exclamation point triangle is used to alert the user to
important operating or maintenance instructions.
REGARDEZ CES SYMBOLES:
La triangle avec le sigle ‘’foudre’’ est employée pour alerter
l’utilisateur au risque de décharge électrique. Le triangle avec
un point d’exclamation est employée pour alerter l’utilisateur
d’instruction importantes pour lors opérations de maintenance.
ATENCION CON ESTOS SÍMBOLOS:
El triángulo con el símbolo de rayo eléctrico es usado para
alertar al usuario de el riesgo de un choque eléctrico.
El triángulo con el signo de admiración es usado para alertar
al usuario de instrucciones importantes de operación o man-
tenimiento.
WATCH FOR THESE SYMBOLS:
IMPORTANT
CTs Series amplifiers require Class 2 output wiring.
Les amplificateurs de série de CTs exigent des câbles de sortie de
classe 2.
CTs-Reihe-Verstärker verlangen Klasse die 2 Produktionsverdrahtung.
Los amplificadores de la Serie CTs requieren de un cableado de salida
Clase 2.
TO PREVENT ELECTRIC SHOCK DO NOT REMOVE TOP OR
BOTTOM COVERS. NO USER SERVICEABLE PARTS INSIDE.
REFER SERVICING TO QUALIFIED SERVICE PERSONNEL.
À PRÉVENIR LE CHOC ÉLECTRIQUE N’ENLEVEZ PAS LES
COUVERCLES. IL N’Y A PAS DES PARTIES SERVICEABLE
À L’INTÉRIEUR. TOUS REPARATIONS DOIT ETRE FAIRE PAR
PERSONNEL QUALIFIÉ SEULMENT.
PARA PREVENIR UN CHOQUE ELÉCTRICO, NO RETIRE LAS
CUBIERTAS SUPERIOR O INFERIOR. NO EXISTEN PARTES QUE
PUEDAN SER REPARADAS POR EL USUARIO AL INTERIOR.
REMITA EL SERVICICO AL PERSONAL TÉCHNICAL CALIFI-
CADO.
TO COMPLETELY DISCONNECT THIS EQUIPMENT FROM THE
AC MAINS, DISCONNECT THE POWER SUPPLY CORD PLUG
FROM THE AC RECEPTACLE. THE MAINS PLUG OF THE POWER
SUPPLY CORD SHALL REMAIN READILY OPERABLE.
POUR DÉMONTER COMPLÈTEMENT L’ÉQUIPEMENT DE
L’ALIMENTATION GÉNÉRALE, DÉMONTER LE CÂBLE D’ALI-
MENTATION DE SON RÉCEPTACLE. LA PRISE D’ALIMENTATION
RESTERA AISÉMENT FONCTIONNELLE.
PARA DESCONECTAR COMPLETAMENTE EL EQUIPO DEL
SUMINSTRO ELECTRICO, DESCONECTE EL CABLE DE ALI-
MENTACION DE LA TOMA DE CA. LAS PATAS DEL CONECTOR
DEL CABLE DE ALIMENTACIÓN DEBERAN MANTENERSE EN
BUEN ESTADO.
FCC COMPLIANCE NOTICE
This device complies with part 15 of the FCC rules. Operation is subject to the following
two conditions: (1) This device may not cause harmful interference, and (2) this device
must accept any interference received, including interference that may cause undesired
operation.
CAUTION: Changes or modifications not expressly approved by the party responsible for
complicance could void the user’s authority to operate the euqipment.
NOTE: This equipment has been tested and found to comply with the limits for a Class B
digital device, pursuant to part 15 of the FCC Rules. These limits are designed to provide
reasonable protection against harmful interference in a residential installation. This equip-
ment generates, uses, and can radiate radio frequency energy and, if not installed and used
in accordance with the instruction manual, may cause harmful interference to radio com-
munications. However, there is no guarantee that interference will not occur in a particular
installation. If this equipment does cause harmful interference to radio or television recep-
tion, which can be determined by turning the equipment off and on, the user is encouraged
to try to correct the interference by one or more of the following measures:
• Reorient or relocate the receiving antenna.
• Increase the separation between the equipment and receiver.
• Connect the equipment into an outlet on a circuit different from that to which the
receiver is connected.
• Consult the dealer or an experienced radio/TV technician for help.
10. Protect the power cord from being walked on or pinched,
particularly at plugs, convenience receptacles, and the point
where they exit from the apparatus.
11. Only use attachments/accessories specified by the manufac-
turer.
12. Use only with a cart, stand, tripod, bracket, or table specified
by the manufacturer, or sold with the apparatus. When a
cart is used, use caution when moving the cart/apparatus
combination to avoid injury from tip-over.
13. Unplug this apparatus during lightning storms or when
unused for long periods of time.
14. Refer all servicing to qualified service personnel. Servicing
is required when the apparatus has been damaged in any
way, such as power-supply cord or plug is damaged, liquid
has been spilled or objects have fallen into the apparatus,
the apparatus has been exposed to rain or moisture, does
not operate normally, or has been dropped.
15. Use the mains plug to disconnect the apparatus from the
mains.
16. WARNING: TO REDUCE THE RISK OF FIRE OR ELECTRIC
SHOCK, DO NOT EXPOSE THIS APPARATUS TO RAIN OR
MOISTURE.
17. DO NOT EXPOSE THIS EQUIPMENT TO DRIPPING OR
SPASHING AND ENSURE THAT NO OBJECTS FILLED
WITH LIQUIDS, SUCH AS VASES, ARE PLACED ON THE
EQUIPMENT.
18. THE MAINS PLUG OF THE POWER SUPPLY CORD SHALL
REMAIN READILY OPERABLE.
Importantes Instructions de Sécurité
Wichtige Sicherheitsinstruktionen
Instrucciones de Seguridad Importantes

page 3
CTs Multi-Channel Power Amplifiers
Operation Manual DUE TO LINE CURRENT HARMONICS, WE RECOMMEND THAT YOU CONTACT YOUR SUPPLY AUTHORITY BEFORE CONNECTION.
DECLARATION of CONFORMITY
Crown International, Inc.
Sue Whitfield
574-294-8289
swhitfi[email protected]
European Representative’s Name and Address:
David J. Budge
10 Harvest Close
Yateley GU46 6YS
United Kingdom
Equipment Type: Commercial Audio Power Amplifiers
Family Name: CTs Family
Model Names: CTs 4200USP/CN, CTs 8200USP/CN
EMC Standards:
EN 55103-1:1997 Electromagnetic Compatibility - Product Family Standard for Audio, Video, Audio-Visual and Entertainment Lighting Control Apparatus for Professional Use, Part 1: Emissions
EN 55103-1:1997 Magnetic Field Emissions-Annex A @ 10 cm and 20 cm
EN 61000-3-2:2001 Limits for Harmonic Current Emissions (equipment input current less than or equal to 16 A per phase)
EN 61000-3-3:2002 Limitation of Voltage Fluctuations and Flicker in Low-Voltage Supply Systems Rated Current less than or equal to16A
EN 55022:2003 Limits and Methods of Measurement of Radio Disturbance Characteristics of ITE: Radiated, Class B Limits; Conducted, Class A
EN 55103-2:1997 Electromagnetic Compatibility - Product Family Standard for Audio, Video, Audio-Visual and Entertainment Lighting Control Apparatus for Professional Use, Part 2: Immunity
EN 61000-4-2:2001 Electrostatic Discharge Immunity (Environment E2-Criteria B, 4k V Contact, 8k V Air Discharge)
EN 61000-4-3:2001 Radiated, Radio-Frequency, Electromagnetic Immunity (Environment E2, criteria A)
EN 61000-4-4:2001 Electrical Fast Transient/Burst Immunity (Criteria B)
EN 61000-4-5:2001 Surge Immunity (Criteria B)
EN 61000-4-6:2003 Immunity to Conducted Disturbances Induced by Radio-Frequency Fields (Criteria A)
EN 61000-4-11:2001 Voltage Dips, Short Interruptions and Voltage Variation
Safety Standard:
IEC 60065: 2001 7th Ed. Safety Requirements - Audio Video and Similar Electronic Apparatus
I certify that the product identified above conforms to the requirements of the EMC Council Directive 89/336/EEC as amended by 92/31/EEC, and the Low Voltage Directive 73/23/EES as amended by 93/68/EEC.
Larry Coburn
Signed
Title: Senior Vice President of Manufacturing
Date of Issue: Jan 1, 2006
Issued By: Crown International, Inc.
1718 W. Mishawaka Road
COMPLIANCE QUESTIONS ONLY:

Operation Manual
CTs Multi-Channel Power Amplifiers
page 4
Important Safety Instructions ........................................................ 2
Declaration of Conformity ............................................................. 3
1 Welcome ...................................................... 5
1.1 Features ............................................................................. 5
1.2 How to Use This Manual ..................................................... 5
2 Setup .......................................................... 6
2.1 Unpack Your Amplifier ....................................................... 6
2.2 Install Your Amplifier .......................................................... 6
2.3 Ensure Proper Cooling ....................................................... 6
2.4 Front Panel Controls and Indicators.................................... 7
2.5 Back Panel Controls and Connectors ................................. 8
2.6 CobraNet and Control Module:
Connectors, Indicators and Controls.................................... 9
2.7 Choose Input Wire and Connectors .................................... 10
2.8 Choose Output Wire and Connectors ................................. 10
2.9 Audio Wiring ...................................................................... 11
2.9.1 Dual 8/4 Mode ........................................................... 11
2.9.2 Dual 70V Mode .......................................................... 11
2.9.3 Bridge-Mono 16/8 Mode ........................................... 12
2.9.4 Bridge-Mono 100V Mode .......................................... 12
2.10 Network Wiring Rules ....................................................... 13
2.11 Network Wiring................................................................. 13
2.12 Audio and Aux Wiring....................................................... 13
2.13 Connect to AC Mains........................................................ 13
2.14 Startup Procedure............................................................. 13
3 Operation .....................................................14
3.1 Precautions ........................................................................14
3.2 CobraNet and Control Module Features ..............................15
4 Advanced Features .........................................21
4.1 Using the Aux Connector ...................................................21
4.1.1 Aux Output .................................................................21
4.1.2 Aux Input ....................................................................21
4.1.3 Listen Bus Wiring .......................................................21
4.2 Protection Systems ........................................................... 22
4.2.1 Thermal Level Control ............................................... 22
4.2.2 Fault .......................................................................... 22
4.2.3 Fault Isolation Topology (FIT) ....................................22
4.2.4 35-Hz High-Pass Filter .............................................. 22
4.2.5 AC Under-Voltage/Over-Voltage Protection ............... 22
4.2.6 Power Fuse ............................................................... 22
4.2.7 Inrush Limiting .......................................................... 22
4.2.8 Variable-speed Fans .................................................. 22
4.2.9 Switching Power Supply ........................................... 22
4.2.10 Mode Switch ........................................................... 22
4.2.11 Bridge Mode Indicator.............................................. 22
4.2.12 Channel Level Control ............................................. 23
5 Troubleshooting ............................................ 24
6 Specifications .............................................. 27
7 AC Power Draw and Thermal Dissipation ............... 31
8 Network and CobraNet Basics ............................ 33
8.1. Network Basics ................................................................ 33
8.2 A Closer Look at CobraNet ................................................ 34
8.2.1 Fast Ethernet.............................................................. 34
8.2.2 Audio Specs .............................................................. 35
8.2.3 Bundles and Audio Channels .....................................35
8.2.4 The Conductor........................................................... 35
8.2.5 Repeater Networks ..................................................... 35
8.2.6 Switched Networks..................................................... 35
9 Service ....................................................... 36
9.1. International and Canada Service ..................................... 36
9.2 US Service ........................................................................ 36
9.2.1 Service at a US Service Center ................................... 36
9.2.2 Factory Service ......................................................... 36
9.2.3 Factory Service Shipping Instructions........................ 36
9.2.4 Packing Instructions .................................................. 36
9.2.5 Estimate Approval...................................................... 36
9.2.6 Payment of Non-Warranty Repairs.............................. 36
10 Warranty ................................................... 37
Product Registration..................................................................... 41
Crown Factory Service Information Form ..................................... 43
Table of Contents

page 5
CTs Multi-Channel Power Amplifiers
Operation Manual
1 Welcome
Building on the foundation of the Com-Tech®Series,
Crown’s CTs Series offers new flexibility and value for
installed sound applications. The Com-Tech Series were
the first to offer independent selection of high- and low-
impedance operation for a specific channel, and CTs
Series amplifiers continue that tradition, with power
levels and features carefully chosen to perfectly integrate
into fixed install design requirements.
Thanks to the factory-installed CobraNet and Control
Module, each amplifier is a network component. It
connects to the audio control/monitor network using
standard 100Mb Ethernet hardware. With this protocol,
an audio system can be interconnected using standard
off-the shelf 100 Mb Ethernet components (switches,
Network Interface Cards, and cables).
The Crown CTs 4200USP/CN and CTs 8200USP/CN
include SmartAmp features and 3rd-generation DSP-
based components. Their SHARC DSP processor gives
the user an enormous amount of digital signal
processing. Audio routing, faders, meters, polarity &
mute, input compressors, filters, multimode output
limiters, error reporting, and load monitoring are all
available. A built-in noise generator and sine-wave
generator provide noise masking and test capabilities.
In addition, the amplifier allows the transport of real-
time digital audio via CobraNet™ over the same 100Mb
Ethernet network that is used for amplifier control and
monitoring. This provides a simple to install, single-
plug solution for control, monitoring, and full-
bandwidth audio distribution. The amplifier can function
independently from the network control. Once the
processing is configured, the unit’s non-volatile
memory allows the amplifier to continue to function with
no external control.
Please take the time to study this manual so that you can
obtain the best possible service from your amplifier.
1.1 Features
Crown®Switching Power Supply for reduced weight
High power-density, with eight channels in a 3U chassis
and four channels in a 2U chassis
Selectable constant-voltage (70V/100V) or low-
impedance (8/4 ohm) operation for each channel pair
In the unlikely event of a channel failure, FIT (Fault
Isolation Topology) circuitry isolates faults within
affected channels
35 Hz High-Pass Filter (70 Hz in CTs 4200) is
automatically inserted when the channel pair is set for
constant-voltage operation. (corner frequency may be
changed as a service option)
Comprehensive array of indicators including Power and
Data, along with Bridge, Ready, Signal, Clip, Thermal and
Fault for each channel, provide accurate diagnostics
Blue Power Indicator flashes if the amplifier shuts off due
to an under-voltage or over-voltage condition on the AC
mains
Advanced protection circuitry guards against: shorted
outputs, open circuits, DC, mismatched loads, general
overheating, under-voltage or over-voltage, high-
frequency overloads and internal faults
Proven Crown AB+B Multi-Mode®output topology
Continuously-variable-speed fans optimize cooling
efficiency
Built-in CobraNet and Control Module connects to a
CobraNet network. This allows a 100 Mbps Ethernet
single-plug solution for CobraNet audio, and HiQnet
control and monitoring
Analog audio inputs allow CobraNet network audio input,
CobraNet audio backup, or a hardwire emergency
override of CobraNet audio
24 bit digital to analog conversion with 32 bit, floating
point DSP processing
•
•
•
•
•
•
•
•
•
•
•
•
•
Up to 18 assignable filters per channel
Over 2 seconds of delay available per channel
Input compressors and output limiters for each
channel
Noise generator for noise masking
Sine generator
Load supervision
Full error reporting
Firmware upgrades via the network
10 user selectable presets
Reliable FLASH memory backup of all parameters
Three Year, No-Fault, Fully Transferable Warranty
completely protects your investment and
guarantees its specifications
1.2 How to UseThis
Manual
This manual provides you with the necessary
information to safely and correctly setup and operate
your amplifier. It does not cover every aspect of
installation, setup or operation that might occur under
every condition. For additional information, please
consult Crown’s Amplifier Application Guide (available
online at www.crownaudio.com), Crown Tech Support,
your system installer or retailer.
We strongly recommend you read all instructions,
warnings and cautions contained in this manual. Also,
for your protection, please send in your warranty
registration card today, or register online at www.
crownaudio.com. And save your bill of sale—it’s your
official proof of purchase.
•
•
•
•
•
•
•
•
•
•
•
4-ohm (per ch.)
8-ohm (per ch.)
70V (per ch.)
1 kHz
CTs 4200USP/CN
20 Hz–20 kHz
Dual
4 Channels Driven
260W
180W
220W
215W
190W
220W
*
*
4-ohm (per ch.)
8-ohm (per ch.)
70V (per ch.)
1 kHz 20 Hz–20 kHz1 Channel Driven
270W
220W
250W
225W
210W
245W
8-ohm (per ch. pair)
16-ohm (per ch. pair)
100V (per ch. pair)
1 kHz 20 Hz–20 kHz
Bridge-Mono
2 Channel-Pairs Driven
520W
400W
220W
430W
380W
220W
*
*
8-ohm (per ch. pair)
16-ohm (per ch. pair)
100V (per ch. pair)
1 kHz 20 Hz–20 kHz1 Channel-Pair Driven
560W
440W
250W
450W
420W
245W
Maximum Average Power
in watts with 0.1% THD.
* Constant Voltage full bandwidth power ratings support
100Hz - 20kHz due to automatic High-Pass Filters.
4-ohm (per ch.)
8-ohm (per ch.)
70V (per ch.)
1 kHz
CTs 8200USP/CN
20 Hz–20 kHz
Dual
8 Channels Driven
200W
160W
200W
175W
155W
185W*
*
4-ohm (per ch.)
8-ohm (per ch.)
70V (per ch.)
1 kHz 20 Hz–20 kHz1 Channel Driven
270W
220W
250W
230W
220W
230W
8-ohm (per ch. pair)
16-ohm (per ch. pair)
100V (per ch. pair)
1 kHz 20 Hz–20 kHz
Bridge-Mono
4 Channel-Pairs Driven
400W
320W
200W
350W
310W
185W*
*
8-ohm (per ch. pair)
16-ohm (per ch. pair)
100V (per ch. pair)
1 kHz 20 Hz–20 kHz1 Channel-Pair Driven
540W
440W
250W
460W
440W
230W
Maximum Average Power
in watts with 0.1% THD.
* Constant Voltage full bandwidth power ratings support
100Hz - 20kHz due to automatic High-Pass Filters.

Operation Manual
CTs Multi-Channel Power Amplifiers
page 6
Power
Data
12
Bridge
34
Bridge
Fault
Thermal
Clip
Signal
Ready
2.1 UnpackYour Amplifier
Please unpack and inspect your amplifier for
any damage that may have occurred during
transit. If damage is found, notify the
transportation company immediately. Only you
can initiate a claim for shipping damage. Crown
will be happy to help as needed. Save the
shipping carton as evidence of damage for the
shipper’s inspection.
We also recommend that you save all packing
materials so you will have them if you ever need
to transport the unit. Never ship the unit
without the factory pack.
YOU WILL NEED (not supplied):
Input wiring cables
Output wiring cables
Rack for mounting amplifier (or a stable surface
for stacking)
WARNING: Before you start to set up
your amplifier, make sure you read and
observe the Important Safety Instruc-
tions found at the beginning of this
manual.
•
•
2.2 InstallYour Amplifier
CAUTION: Before you begin, make sure
your amplifier is disconnected from the
power source, with the power switch in
the “off” position and all level controls
turned completely down (counterclock-
wise).
Use a standard 19-inch (48.3-cm) equipment
rack (EIA RS-310B). See Figure 2.1 for amplifier
dimensions.
You may also stack amps without using a
cabinet.
NOTE: When transporting, amplifiers should be
supported at both front and back.
2.3 Ensure Proper Cooling
When using an equipment rack, mount units
directly on top of each other. Close any open
spaces in rack with blank panels. DO NOT block
front, rear or side air vents. The side walls of the
rack should be a minimum of two inches (5.1
cm) away from the amplifier sides, and the back
of the rack should be open.
Figure 2.2 illustrates standard amplifier airflow.
2 Setup
Figure 2.1 Dimensions
Left: CTs 4200USP/CN Right: CTs 8200USP/CN
Figure 2.2 Airflow

page 7
CTs Multi-Channel Power Amplifiers
Operation Manual
2.4 Front Panel Controls
and Indicators
Note: CTs 8200USP/CN is shown. Some CTs 4200
USP/CN features are in different locations.
A. Bridge Mode Indicator
Yellow LED, one per channel pair, illuminates when
the channel pair’s Mode Switch is set to the “Bridge”
position. If Mode switch is changed while amplifier is
powered up, Bridge LED will flash, indicating that the
amplifier must be powered off and on to reset the
Mode.
B. Ready Indicator
Green LED, one per channel, illuminates when the
channel is initialized and ready to produce audio
output.
C. Signal Indicator
Green LED, one per channel, illuminates to indicate
the presence of analog input signals above –40 dBu.
D. Clip Indicator
Red LED, one per channel, illuminates when the THD
of the channel’s output signal rises to a level typically
considered as the onset of audible clipping. The Clip
Indicator also will illuminate during Thermal Level
Control (TLC) or input overload.
E. Thermal Indicator
Red LED, one per channel, flashes when the channel
has shut down due to thermal stress or overload. If the
power supply goes into thermal overload, all channel
LEDs will flash.
F. Fault Indicator
Red LED, one per channel, illuminates when the
amplifier output channel has stopped operating.
G. Ventilation Grille
Front-to-rear forced airflow.
H. Data Indicator
Yellow LED flashes whenever a command addressed to
the module is received. A similar LED is on the back panel,
and the two LEDs flash simultaneously.
I. Power Indicator
Blue LED indicates amplifier has been turned on and AC
power is available. Indicator also flashes if the amplifier
shuts off due to an under/over-voltage condition on the
AC mains.
J. Power Switch
Amplifier is on when the switch is in the IN position.
Figure 2.3 CTs 8200USP/CN Front Panel
2 Setup (continued)

Operation Manual
CTs Multi-Channel Power Amplifiers
page 8
2.5 Back Panel Controls
and Connectors
Note: CTs 8200USP/CN is shown. Some CTs
4200USP/CN features are in different
locations.
K. AC Power Cord Connector
Standard IEC type 320 inlet.
120V models: 15-amp.
220-240V models: 10-amp.
Voltage is indicated above IEC inlet.
L. Output Connectors
One four-pole terminal strip for every two
channels with touch-proof cover. Accepts up to
10 AWG terminal forks. To connect outputs, first
remove the touch-proof cover plate covering
the terminal strip by removing the screw which
holds it in place.
M. USP/CN Module
Built into the amplifier, this module allows
connection to a CobraNet network. Please see
Section 2.6 for details.
N. Channel Level Controls
One 21-position detented rotary potentiometer
per channel, ranging from infinity (-70 dB) to
0 dB attenuation. Refer to Section 4.2.12 for
precise dB attenuation increments for each
detent.
O. Input Connectors
Removable Phoenix-style barrier connectors for
balanced input. Also can be used as a CobraNet
input or a backup for Cobranet (see Section
3.2.6).
P. Mode Switch
Used on each consecutive pair of channels, this
four-position switch is used to select the
amplifier’s mode of operation: Dual 8/4 ohms,
Dual 70V, Bridge-Mono 16/8 ohms, and
Bridge-Mono 100V.
IMPORTANT: Be sure to power off the
amplifier before change the Mode-
switch setting. If this is not done, the Bridge
light will flash to indicate that the power must
be cycled off and back on to reset the mode.
Q. Cooling Vents
Front-to-rear forced airflow.
2 Setup (continued)
Figure 2.4 CTs 8200 USP/CN Back Panel
(Shown with Touch-proof Cover Removed)

page 9
CTs Multi-Channel Power Amplifiers
Operation Manual
Figure 2.5 USP/CN Controls, Indicators and Connectors
(Note: Actual Product Artwork May Vary Slightly)
2.6 CobraNet and Control Module:
Connectors, Indicators and
Controls
A. AUX Connector
AUX input, AUX output, and Foldback. See
Sections 3.2.7, 3.2.8, and 4.1.
B. Preset Indicator
Signals the number of the current preset, if
active, by flashing a series of flashes equal
to the current preset number. See Section
3.2.2.
C. Reset/Preset Switch
Activated by inserting a small item, such as
a paper clip, this switch is used to change
presets, restore settings to factory default or
restore all the presets to the factory defaults.
During operations of the switch, the Data
indicator flashes as an aid to the user. See
Section 3.2.9.
ABCDE
2 Setup (continued)
D. Data Indicator
Flashes when the amplifier receives a valid
command that is addressed to the amplifier.
See Section 3.2.1.
E. CobraNet Network Connectors
The dual RJ45 CobraNet connectors allow a
Primary & Secondary connection to the 100
Mbps Ethernet network. Should the Primary
connection lose link activity with the
network, the module will automatically
switch to the Secondary connection to
ensure uninterrupted audio and control. The
indicators on the RJ45 connectors display
network information concerning the Ethernet
and CobraNet connections. See Sections
3.2.3, 3.2.4, and 3.2.5.

Operation Manual
CTs Multi-Channel Power Amplifiers
page 10
2.7 Choose Input Wire and Connectors
If you will be connecting an analog audio signal to the CTs amplifier, please
read this section. Figure 2.6 shows connector pin assignments for balanced
wiring, and Figure 2.7 shows connector pin assignments for unbalanced
wiring.
When possible, use balanced wiring for signal input, which provides better
rejection of unwanted noise and hum. For more information, refer to the Crown
Amplifier Application Guide, available online at www.crownaudio.com
NOTE: Custom wiring should only be performed by qualified
personnel.
Shield
Shield
2 Setup (continued)
2.8 Choose Output Wire and Connectors
Crown recommends using professionally constructed, high-quality, two- or
four-conductor, heavy gauge speaker wire and connectors. You may use
terminal spade lugs or bare wire for your output connectors (see Figure 2.8).
CTs amplifier terminal strips accept up to 10 AWG terminal forks which fit over
a #8 screw. For best results, Crown recommends Panduit part #PV10-10LF-L
or equivalent terminal spade lug. Screw spacing is shown in Figure 2.8.
To connect outputs, first remove the touch-proof cover plate covering the
terminal strip by removing the screw which holds it in place.
To prevent the possibility of short-circuits, wrap or otherwise insulate exposed
loudspeaker cable and connectors. Also, a touch-proof cover plate, which
covers the terminal strips, is provided to help prevent short circuits. The cover
plate should be reinstalled after connecting outputs.
Suggested below are guidelines to select the appropriate size of wire based on
the distance from amplifier to speaker. Check with local code as this may vary.
Distance Wire Size
up to 25 ft. (7.6 m) 16 AWG
26-40 ft. (7.9-12.2 m) 14 AWG
41-60 ft. (12.5-18.3 m) 12 AWG
Over 60 ft. (18.3 m) 10 AWG
CAUTION: Never connect the speaker return to the chassis of the
amplifier, or damage to the amplifier may result.
CAUTION: Never use shielded cable for output wiring.
Figure 2.6 Balanced Input
Connector Wiring
See the Crown Amplifier
Application Guide, available
online at www.crownaudio.com,
for pin assignments for
commonly used connector
types.
Output panel
shown with
touch-proof
cover plate
removed.
NOTE: CTs 8200 USP/CN is shown. Some CTs 4200 USP/CN features are in different locations.
Figure 2.7 Unbalanced Input
Connector Wiring
Figure 2.8 Output Connector Wiring
(Typical of Two Channels)

page 11
CTs Multi-Channel Power Amplifiers
Operation Manual
2.9 Audio Wiring
CAUTION: Never change the position of
the Mode Switch while the amplifier
power is on.
2.9.1 Dual 8/4 Mode
Typical analog input and output wiring, along
with level control and Mode Switch settings are
shown in Figure 2.9. Make sure the Mode switch
is set to the “Dual 8/4” position. Cobranet
input wiring is covered in Section 2.11.
INPUTS: Connect input wiring for each channel.
OUTPUTS: Maintain proper polarity (+/–) on
output connectors.
Connect the Channel 1 speaker’s positive (+) lead
to amplifier Channel 1 positive terminal; repeat
for negative (–). Repeat each channel wiring as
for Channel 1.
2.9.2 Dual 70V Mode
CAUTION: Never change the position of
the Mode Switch while the amplifier
power is on.
Typical input and output wiring, along with level
control and Mode Switch settings are shown in
Figure 2.10. Make sure the Mode switch is set to
the “Dual 70V” position.
INPUTS: Connect input wiring for each channel.
OUTPUTS: Maintain proper polarity (+/–) on
output connectors.
Connect Channel 1 positive (+) speaker load to
Channel 1 positive terminal of amp; repeat for
negative (–). Repeat each channel wiring as for
Channel 1.
2 Setup (continued)
Figure 2.9 System Wiring and Control Settings, Dual Mode, 8/4 Ohm
Figure 2.10 System Wiring and Control Settings, Dual Mode, 70V
Output panel
shown with
touch-proof
cover plate
removed.
Output panel
shown with
touch-proof
cover plate
removed.
CH 4
DUAL DUAL
BRIDGE
CH 3
CH 2
DUAL DUAL
BRIDGE
CH 1
See the Crown Amplifier
Application Guide, available
online at www.crownaudio.com,
for pin assignments for
commonly used connector
types.
CH 4
DUAL DUAL
BRIDGE
CH 3
CH 2
DUAL DUAL
BRIDGE
CH 1
70V
70V

Operation Manual
CTs Multi-Channel Power Amplifiers
page 12
2.9.3 Bridge-Mono 16/8 Mode
CAUTION: Never change the position of
the Mode Switch while the amplifier
power is on.
Typical analog input and output wiring, along
with level control and Mode Switch settings are
shown in Figure 2.11. Make sure the Mode
switch is set to the “Bridge 16/8” position.
INPUTS: Connect input wiring only to the lower-
(odd-) numbered channel pair.
OUTPUTS: Connect the speaker across the
positive terminals of each channel pair. Do not
use the negative terminals of the channel pair
when the pair is being operated in Bridge-Mono
mode.
NOTE: When operating the channel pair in
Bridge-Mono mode, turn down (full CCW) the
level control for the higher (even)-numbered
channel of the channel pair. The lower (odd)-
numbered level control works both channels.
2.9.4 Bridge-Mono 100V Mode
CAUTION: Never change the position of
the Mode Switch while the amplifier
power is on.
Typical analog input and output wiring, along
with level control and Mode Switch settings are
shown in Figure 2.12. Make sure the Mode
switch is set to the “Bridge 100V” position.
INPUTS: Connect input wiring only to the lower-
(odd-) numbered channel pair.
OUTPUTS: Connect the speaker across the
positive terminals of each channel pair. Do not
use the negative terminals of the channel pair
when the pair is being operated in Bridge-Mono
mode.
NOTE: When operating the channel pair in
Bridge-Mono mode, turn down (full CCW) the
level control for the higher (even)-numbered
channel of the channel pair. The lower (odd)-
numbered level control works both channels.
2 Setup (continued)
Figure 2.11 System Wiring and Control Settings, Bridge-Mono Mode, 16/8 Ohm.
Figure 2.12 System Wiring and Control Settings, Bridge-Mono Mode, 100V
CH 4
DUAL DUAL
BRIDGE
CH 3
CH 2
DUAL DUAL
BRIDGE
CH 1
See the Crown
Amplifier
Application
Guide, available
online at www.
crownaudio.
com, for pin
assignments for
commonly used
connector types.
CH 4
DUAL DUAL
BRIDGE
CH 3
CH 2
DUAL DUAL
BRIDGE
CH 1
100V

page 13
CTs Multi-Channel Power Amplifiers
Operation Manual
2.10 Network Wiring Rules
IMPORTANT: Please read the wiring rules below before
installing the wiring.
Connect each device to the network through its own cable
in a Star Network (Figure 2.13). Do not connect them in a
serial fashion.
Make sure each device has its own Category 5 certified
cable connecting it to a central concentrator, most often a
switch.
2.11 Network Wiring
Use the cable to connect the Primary CobraNet connector
to a 100 Mb port on the Ethernet switch that is used to
form the CobraNet network. For more detail, see Section
3.2.3. We highly recommend that the CobraNet be a
standalone or separate-network LAN.
Crown strongly recommends the use of a 100 Mb
Ethernet network for control and monitoring.
If network redundancy is required, use a standard CAT5
cable to connect the Secondary CobraNet connector to a
100Mb port on the auxiliary CobraNet network.
HiQnet control is available over the CobraNet network
using Harman Pro System Architect software. The
software can set up CobraNet audio routing and
addressing.
2.12 Audio and Aux Wiring
1. Connect the Audio Input Wiring. The amplifier is
equipped with removable barrier block connectors for
each channel’s input. See Section 2.7 for more detail on
audio wiring.
In System Architect, the analog balanced audio inputs can
be set up to act either as CobraNet backup, an emergency
override of CobraNet audio, or as an audio input to the
CobraNet network.
2. Connect the AUX wiring if used. See Section 4.1 for
more information.
2.13 Connect to AC Mains
Connect your amplifier to the AC mains power source
(power outlet) with the supplied AC power cordset. First,
connect the IEC end of the cordset to the IEC connector on
the amplifier; then, plug the other end of the cordset to the
AC mains.
WARNING: The third prong of this connector
(ground) is an important safety feature. Do not
attempt to disable this ground connection by
using an adapter or other methods.
Amplifiers don’t create energy. The AC mains voltage and
current must be sufficient to deliver the power you expect.
If the AC line voltage varies out of an acceptable range,
the amplifier’s power supply turns off and the blue Power
LED flashes. The amplifier will turn back on when the AC
line voltage returns to safe operating levels. Figure 2.14
provides voltage limits for all amplifier AC voltage
configurations. Also, the amplifier must be run within the
specified mains frequency requirements (indicated on the
amplifier’s back panel label). If you are unsure of the
output voltage of your AC mains, please consult your
electrician.
The various models have the following under-voltage
limits and over-voltage limits:
Models Under-Voltage Over-Voltage
100VAC
(CTs 90VAC 110VAC
120 VAC units 108VAC 132VAC
2 Setup (continued)
Figure 2.13 An Example of a Star Network
220V/230V/ 198VAC 264VAC
2.14 Startup Procedure
Use the following procedure when first turning on your
amplifier:
1. Turn down the level of your audio source.
2. Turn down the level controls of the amplifier.
3. Turn on the “Power” switch. The Power
indicator should glow.
4. Turn up the level of your audio source to an
optimum level.
5. Turn up the Level controls on the amplifier
until the desired loudness or power level is achieved.
6. Turn down the level of your audio source to
its normal range.
If you ever need to make any wiring or installation changes,
don’t forget to disconnect the power cord.

Operation Manual
CTs Multi-Channel Power Amplifiers
page 14
4. WARNING: Never connect the output to a
power supply, battery or power main.
Electrical shock may result.
5. Tampering with the circuitry, or making
unauthorized circuit changes may be
hazardous and invalidates all agency
listings, and may also void the product’s
warranty.
6. Do not operate the amplifier with the red
Clip LEDs constantly flashing.
7. Do not overdrive the mixer, which will
cause clipped signal to be sent to the
amplifier. Such signals will be reproduced
with extreme accuracy, and loudspeaker
damage may result.
8. Use caution when operating the amplifier
with a 2-ohm load impedance on 1 channel.
Do not operate the amplifier with less than a
2-ohm load impedance per channel when
driving more than 1 channel. Due to the
amplifier’s output protection, such a
configuration may result in premature
clipping, speaker damage or a blown power
fuse.
Remember: Crown is not liable for damage that
results from overdriving other system
components.
3.1 Precautions
Your amplifier is protected from internal and
external faults, but you should still take the
following precautions for optimum performance
and safety:
1. Before use, your amplifier first must be
configured for proper operation, including
input and output wiring hookup. Improper
wiring can result in serious operating
difficulties. For information on wiring and
configuration, please consult the Setup
section of this manual or, for advanced setup
techniques, consult Crown’s Amplifier
Application Guide available online at www.
crownaudio.com.
2. Use care when making connections,
selecting signal sources and controlling the
output level. The load you save may be your
own!
3. Do not short the ground lead of an output
cable to the input signal ground. This may
form a ground loop and cause oscillations.
3 Operation

page 15
CTs Multi-Channel Power Amplifiers
Operation Manual
3 Operation (continued)
3.2 CobraNet and Control Module Features
3.2.1 Data Indicator
An amber Data Indicator flashes whenever a command addressed
to the module is received. To assist with troubleshooting, an
option that forces the Data Indicator to remain lit is available
through the software. In addition, the locate feature in System
Architect will cause the Data Indicator to blink rapidly to help you
identify the unit. Another Data Indicator is on the amplifier’s front
panel, and it lights simultaneously with the module’s Data
Indicator.
3.2.2 Preset Indicator
A green Preset indicator signals the number of the current preset,
if active, by continually flashing a series of flashes equal to the
current preset number, followed by a pause. A preset is
considered “active” if the USP/CN settings match those in the
selected preset. If a change is made to any setting then the preset
is considered “inactive,” and the indicator stops flashing.
3.2.3 CobraNet Network Connectors
The Primary and Secondary CobraNet RJ-45 connectors can
simultaneously interface to the 100 Mbps HiQnet network. While
the Primary CobraNet connector is the main connection to the
network, the Secondary connector is the “backup” or redundant
connection to the network. If the Primary connection fails due to
cut wire, failed network switch, etc., this port is automatically
enabled and ready to receive the network data within a few
seconds.
Make connections with a standard CAT5 cable to a network switch
port. Crown strongly recommends the use of switches and not
hubs in the network. Hubs will limit the amount of CobraNet traffic
and create unnecessary limitations in the network.
If the amplifier is not connected to a network, the CobraNet
connector can connect directly to a computer’s network adapter
port using a crossover cable (TX and RX pairs swapped).
3.2.4 Link/Activity Indicator
The green Link/Activity indicator is provided on the network
connector to display the status of the Ethernet connection.
Whenever the module is properly connected to another
functioning network port, the indicator lights. When the module
detects the presence of network traffic, the indicator flashes. The
Link/Activity LED flashes for all network traffic, while the Data
LED flashes only for commands addressed to this USP/CN.
.3.2.5 CobraNet In-Use/Conductor Indicator
The indicator on the right side of each CobraNet RJ-45 connector
turns ON if the port is in-use (i.e. the link is being used to transmit
or receive active CobraNet traffic), and will blink if the device is
also the conductor (the timing reference).
3.2.6 Balanced Audio Inputs
Located on the amplifier rear panel, these removable barrier-block
connectors allow line-level audio signals to be input to the USP/
CN. The amplifier accepts line-level analog audio signals in
addition to the digital audio from the CobraNet network. This
analog audio can be used for one of three purposes:
• Backup of the CobraNet network audio: In the unlikely event of
a loss of CobraNet audio to the module, the module automatically
switches over to the balanced audio inputs.
• Emergency override: If an audio signal appears at the analog
inputs, the module switches to that signal.
• CobraNet network audio inputs: The amplifier can act as a
CobraNet audio input source by converting the balanced audio
input signal to CobraNet.
3.2.7 Aux Input/Output Connector
An RJ-11 connector provides three functions: AUX output, AUX
input and Foldback. The AUX output is a multifunctional control
output that delivers 15 VDC limited to 15 mA. It can be configured
in two modes:
•Manual mode: The output is simply controlled with a
command from the software.
•Error reporting mode: The AUX out is active when the
module detects an error. Each error source (Thermal, Clip, Load,
Amp Fault, and Line Voltage) can be individually enabled to
activate the AUX output when the error conditions are met.
An inversion control allows the AUX output functionally to be
inverted for the manual and error reporting modes. The inversion
control is ignored for flash preset mode.
The AUX input is a two-state input with a high state defined as
voltage between 4 and 15 VDC. The low state is defined as
voltages between 0 and 1.6 VDC. It has a 10K input impedance.
The AUX input can be configured in several modes:
•None: In this mode the module makes no changes to its
operation. However, the AUX input status can be monitored
through the control software and used for functions within the
software.
•Mute All: This mutes the channels when the AUX input is
active. Likewise, the Power Off Both function disables both
channels during an active AUX input.
•AUX Input Inversion: This control allows the low state to
activate the selected function. Normally, the high state activates
the selected AUX input function.
The AUX port provides a power supply for the AUX input. This 15
VDC at 15 mA supply can be connected through a switch to the
AUX input. This allows a simple switch closure to operate the aux
input without the need of an external power supply. See Section
4.1 for details on using the AUX port.
3.2.8 Listen Bus or Foldback
The AUX port is also used for the Foldback connection. Two
pins of the connector provide a balanced line-level audio output
that can be selectively driven by either channel under System
Architect software control.
3.2.9 Preset/Reset Switch
The Preset/Reset switch is a recessed pushbutton located
between the Data and Preset indicators. It is activated by a
straightened paper clip or similar object. This switch can be used
to change presets, restore settings to factory default or restore all
the presets to the factory defaults. During operations of the
switch, the Data indicator flashes as an aid to the user.
To select a preset:
1. Remove all audio input signals.
2. With the amplifier powered up, momentarily hold the preset
switch in for one flash of the Data indicator (less than 2 seconds)
and then release.
3. The amplifier will load the next preset in the defined preset
range.
The range of presets is defined by the Maximum Preset and
Minimum Preset controls. Once the Maximum Preset is reached,
the next momentary depression of the switch will cycle the USP/
CN to the Minimum Preset.
4. The Preset indicator will flash the number of the selected preset
followed by a pause.
5. Restore the audio input signals.
To restore the unit to factory default settings:
1. Remove all audio input signals.

Operation Manual
CTs Multi-Channel Power Amplifiers
page 16
2. Hold the Reset/Preset switch in for two flashes of the Data light
(longer than 2 seconds).
3. The Data indicator will flash rapidly for a moment.
4. Restore the audio input signals.
To restore the unit including presets to factory default
settings:
1. Remove all audio input signals.
2. Hold the Reset/Preset switch while applying power to the unit.
3. The Data and Preset indicator will both light.
4. Release the switch within 5 seconds (before the Data and Preset
indicators go out).
5. The Data indicator will flash rapidly for a moment.
6. Restore the audio input signals.
3.2.10 User Presets
The control settings for all the functions can be stored as presets.
A total of ten presets can be saved in the USP/CN’s nonvolatile
memory. Each preset can be named with a 30 character name
describing its function, which is also stored in the USP/CN’s
memory.
•The Store Preset Control saves the current setting to the
specified preset.
•The Recall Preset Control recalls the specified preset
settings.
•The Preset Valid Monitor indicates if a change has been
made to any setting since the last time a preset has be saved or
recalled.
•The Last Stored or Recalled Preset Monitor indicates
what the Last Stored or Recalled preset is.
3.2.11 Clip Event Monitor
A clip detector is provided each channel. These monitors will
indicate any clip condition (> 0.05% distortion) in the amplifier
channel. The clip detectors also can indicate certain errors (See
Section 3.1.25).
3.2.12 Input Signal Level Monitor
The input signal level of each channel can be monitored via
System Architect software. The measurement range is from +20
dBu to –40 dBu with 0.5 dBu resolution. Each audio channel has
the following monitors:
• Analog audio input: The audio input at the Balanced Audio
Inputs.
• Switched audio input: The audio input after the Input Audio
Router.
• CobraNet audio input: The audio input level from the selected
CobraNet audio channel.
3.2.13 Output Signal Level Monitor
The output signal level of each channel can be monitored via
System Architect software. The measurement range is from 0 dB
to –40 dB with 0.5 dB resolution. The monitors are scaled so that
0 dB is referenced to the full rated output voltage of the amplifier.
3.2.14 Thermal Headroom Level Monitor
The thermal headroom level of each channel can be monitored
with the software. This level represents the percent of available
power/thermal capacity that is currently being used within the
output section of the amplifier. When the thermal headroom level
reaches 100%, the amplifier cannot produce any more power and
it will begin to protect the output devices by limiting their drive
level. The thermal limiter feature of the USP/CN can be set to
engage at a pre-selected thermal level. (See Section 3.2.31).
3.2.15 Power/Standby Control
Each channel can be independently turned on and off.
3.2.16 Signal Mute
The output signal of each channel can be independently muted.
This function produces a minimum 60 dB of attenuation.
3.2.17 Polarity Inverter
The input signal polarity of each channel can be independently
inverted.
3.2.18 Input Signal Fader
Each input signal can be adjusted under software control. The
gain range is +20dB to –100dB in 0.5 dB steps. Each analog
Audio Input has two faders with these functions:
• Trim the Analog Audio Input signal before the Input Router.
• Trim the Analog Audio Input signal after the Input Router.
3.2.19 Amplifier Information
At startup, the module extracts several useful items of information
about the host amplifier. These include manufacturer, model, date
code, and serial number. This information is stored in the software
system inventory and is displayed on the software control panels.
3.2.20 User and Channel Labels
In IQwic, the module can store two user labels and channel labels.
In System Architect, the module can store 4 or 8 channel labels
and a unit label.These labels are 30-character strings that can be
set by the user to indicate the function of the amplifier and its
channels. For example, “LOWER RIGHT CLUSTER, FOR DELAY.”
3.2.21 Line Voltage Monitor
The AC line voltage supplied to the amplifier can be monitored with
this function. If the voltage is out of a safe area you can trigger an
error.
3.2.22 Error Reporting
The module can detect three different error conditions per channel
and errors in the AC line voltage. Each error type can be configured
to report the error through the control network and/or the AUX port.
Network reported errors appear in the control software’s Error
Window.
The software offer many options to further report errors, including
audible alerts, printout, email, pager, serial port and fax. The options
are set in the software. The following describes each error source.
CLIP: The USP/CN can be configured to report if an excessive
number of clip events occur in either amplifier channel. The clip
events are consider an error if they exceed the defined count per the
defined unit of time. The Count Control sets the maximum number
of events before the error is reported. The range is 1 to 100. The
Time Control defines the amount of time that the events are counted
before starting the counting process over. Its range is 1 to 10
seconds. Note: Clip events are defined as the start of each clip and
every 10 milliseconds the amplifier is in clip thereafter. Using a high
count setting with a short time setting may result in clip error never
being detected.
THERMAL: Errors can be generated for excessive temperature in
the output section of the amplifier channel. The Threshold Control
sets the level that, if exceeded, will generate the error report. This
control has a range of 1 to 100%.
LOAD: If the load monitoring feature is activated, an error report can
be generated if the load impedance moves outside the pre-selected
range. See Section 3.1.33 for instructions on setting up load
monitoring.
LINE VOLTAGE: The AC line voltage can be monitored and an error
generated whenever the voltage is outside of the limits set at the
factory.
3 Operation (continued)

page 17
CTs Multi-Channel Power Amplifiers
Operation Manual
3.2.23 Input Signal Compressor/Limiter
An input signal compressor/limiter is available for each channel.
Five parameters control this feature:
Enable: Enables or disables this function.
Threshold: Sets the level, in dBu, above which the compressor
begins to attenuate the input signal. This level corresponds to the
input level meter reading. The compressor is “feed-forward,”
meaning that the level detection point is located before the gain
control stage. The range is from +20 dBu to – 50 dBu.
Attack Time: Sets the attack time of the compressor. The attack
time is defined as the time it takes the compressor to attenuate the
signal gain by 20 dB. The range is from 1 millisecond to 0.1
second.
Release Time: Sets the release time of the compressor. The
release time is defined as the time it takes the compressor to
increase the signal gain by 20 dB. The range is from 10
milliseconds to 10 seconds.
Compression Ratio: Sets the compression ratio of the
compressor. The ratio is the relation between the amount of
attenuation applied by the compressor verses the amount that the
input signal is over the threshold. The available settings are 2:1 to
32:1.
3.2.24 Peak Voltage Limiter
This limits the peak voltage output of the amplifier. Four
parameters control this limiter for each channel:
Enable: Enables or disables this function.
Threshold: Sets the level, in absolute voltage, which the limiter
will allow from the amplifier. The range is from 12 Vpk to 255 Vpk.
Attack Time: Sets the attack time of the limiter. The attack time is
defined as the time it takes the limiter to attenuate the output
signal by 20 dB. The range is from 1 millisecond to 100
milliseconds.
Release Time: Sets the release time of the compressor. The
release time is defined as the time it takes the limiter to increase
the output signal by 20 dB. The range is from 10 milliseconds to
10 seconds.
3.2.25 RMS Power Limiter
This limits the long-term output power of the amplifier. Four
parameters control this limiter for each channel:
Enable: Enables or disables this limiter.
Threshold: Sets the average power level, in watts, which the
limiter will allow from the amplifier channel. The range is from 10
watts to 600 watts. This level should be set to the connected
loudspeaker’s long-term power rating.
Attack Time: Sets the attack time of the limiter. The attack time is
defined as the time it takes the limiter to attenuate the output
signal by 20 dB. The range is from 1 second to 30 seconds.
Release Time: Sets the release time of the compressor. The
release time is defined as the time it takes the limiter to increase
the output signal by 20 dB. The range is from 1 second to 30
seconds.
3.2.26 Load Supervision
The load supervision feature allows real-time monitoring of the
load connected to each amplifier channel. When enabled, the
USP/CN continuously monitors the amplifier output voltage and
current, and calculates the long-term average load impedance.
The measured load impedance is compared against the user-
defined high and low limits. If either limit is exceeded, the status
indicator and, if enabled, the System Architect Error Reporting
functions alert the user of the problem. There are six controls and
two indicators for each channel:
Enable: Enables or disables the load-supervision function.
High Limit:Sets the upper bound above which the system will
report a “high” error status.
Low Limit: Sets the lower bound below which the system will
report a “low” error status.
Nominal Load Impedance: Sets the expected average
impedance for the connected load. This value determines the
output signal level required for the test. This parameter is also
used by the average power limiter to determine the expected
power threshold. (See Section 3.1.29).
Report Error to Network: Enables Error Reporting to send an
error report via the network so that high and low load conditions
are reported to the software.
Report Error to Aux: Enables and high or low load error to be
reported by the AUX output. (See Section 4.1.1).
Test Indicator: This indicator is active when the amplifier output
signal is sufficient to allow load impedance calculation and test
verification.
Low/Normal/High Indicator: This indicator shows the present
status of the load impedance with respect to the user-defined high
and low limits.
Z Average Monitor: Reports the actual calculated average load
impedance in ohms. Its range is from 0 ohms to 250 ohms.
Load Supervision Applications
The Load Supervision feature can be used to monitor the amplifier
load in real time with almost any program material. Average load
impedance is calculated as a function of amplifier output voltage
and current. The system requires approximately 20-30 mA of
average amplifier output current for adequate supervision. This
allows typically low average output power levels of less than ½
watt with most loads. The maximum load impedance for reliable
system performance is limited to about 50 ohms. Higher
impedances can be measured but may require higher amplifier
output levels for reliable operation.
3 Operation (continued)

Operation Manual
CTs Multi-Channel Power Amplifiers
page 18
Most amplifier/load systems can be configured and supervised
by following these steps:
1. Configure your audio system using a known “good” load,
then enable the Load Supervision feature.
2. Provide typical program material at a level high enough to
light the “test” indicator.
3. Run the system at this level until the average impedance
stabilizes. This may take seconds to minutes depending on
level, duty-cycle, etc.
4. Set the nominal impedance at the measured value average.
This optimizes the supervision algorithm for voltage and
current levels versus the actual load. Note: a higher nominal
setting will require higher output levels.
5. Set the high limit at twice average and the low limit at one-
fourth nominal. (These limits are somewhat arbitrary but
should be a good starting point.)
6. Let the system run for extended periods using any and all
typical program material.
7. Adjust the high/low limits, if necessary, to account for any
variance in average measured impedance.
8. Enable error reporting, if desired.
This procedure should work well for most applications. However,
some applications can be a little more difficult. Some very low-
level and/or low duty-cycle signals may not adequately “test” the
load. Lab and situation testing have shown output levels as small
40 dB below rated amplifier output to be enough for most low-
impedance loads. Higher impedance loads such as those used in
“lightly-loaded” 70V distribution lines may require signal level
near 20 dB below rated output.
The “Nominal Load Impedance” control is used to optimize the
system for the most accurate calculation of load impedance. It
should be set to the expected nominal (or rated) impedance of the
“normal” load. The high limit should be set for at least 2 times the
expected nominal or actual measured load, while the low limit
should be set to ½ the expected nominal or actual measured load.
The following example calculates the SPL necessary for
supervision of a typical 8-ohm system. While the resulting 80-dB
SPL @ 1 meter is definitely above conversation level, it is not
uncomfortable.
An “8 ohm” example:
30 mA into 8 ohms = 0.007watt.
8-ohm driver sensitivity = 100dB for 1W @ 1 meter.
0.007W/1W = –20dB.
Required SPL for supervision test is 100dB – 20dB = 80dB SPL
@ 1 meter.
3.2.27 Typical Load Characteristics
It is well known that the typical loudspeaker impedance is not the
same for all frequencies. This variance is due to the effect of
electrical properties such as the expected increase in impedance
at high frequencies due to driver voice-coil inductance, or the
peaks and valleys due to passive crossovers. Testing of various
passive boxes has shown peaks of 100 ohms or more! Low-
frequency impedance variation can come from the interaction of
the driver compliance with that of the box. The low frequency
variations are usually wide bandwidth and may vary from 6 to 30
ohms on an 8-ohm driver.
These anomalies are easily averaged out by the USP/CN
supervision algorithm in most systems. However, there may be
some extreme situations for very narrow bandwidth (i.e. single-
note) signals and/or very widely varying loads that the algorithm
simply cannot overcome. In these cases, widening the high and
low limits will help decrease the “sensitivity” of supervision and
decrease the chance of “nuisance” error reports.
3.2.28 Filters
Each audio channel has five separate places where filters can be
placed in the system. There are 64 filters total and they can be
placed anywhere within the system. In addition to filtering, each
possesses up to ± 24 dB of gain. The filters will vary based on the
firmware and software being run. The following filters are
available:
• Lowpass: Bessel 2-4, Butterworth1-4, and Linkwitz-Riley 4
(Firmware 2.0 provides up to 8 Linkwitz-Riley filters)
•Highpass: Bessel 2-4, Butterworth1-4, and Linkwitz-Riley 4
(Firmware 2.0 provides up to 8 Linkwitz-Riley filters)
• Lowshelf: Low-frequency shelving EQ
•Highshelf: High-frequency shelving EQ
• Lowpass EQ: Variable Q from 0.1 to 35
•Highpass EQ: Variable Q from 0.1 to 35
•Parametric EQ: Variable Q from 0.1 to 35
•All-Pass: 1st and 2nd order
All-Pass filters provide no gain change to the output, but provide a
phase change at the selected frequency. This corrects the phase
relationship of the output without a gain reduction, such as is
found in other filters.
3.2.29 Delay
Due to the nature of DSP processing, there is some inherent delay
or latency within the system These delays are:
DSP processing: 1 ms or 1000 µs.
Digital-to-analog conversion: 250 µs.
Analog-to-digital conversion: 250 µs.
Amplifier: 100 µs.
In addition to these unavoidable delays, additional delay can be
added to each channel. Each channel is capable of 2.0 seconds of
delay in 20.8 µs increments.
Overall delay = inherent delay + coarse delay + fine delay.
3.2.30 Noise Generator
A noise generator shared between channels allows noise to be
mixed into the audio signal. This is useful for noise masking
applications and testing. Each channel has the following controls:
•Noise On/Off: The channel’s noise generator can be
independently turned on.
•Noise Type: Full spectrum white noise or pink noise.
•Noise Level: A fader to allow the noise level to be controlled.
3.2.31 Sine-wave Generator
A sine-wave signal generator allows the mixing of a single tone
into the audio signal. Typical applications can be for the injection
of a high frequency tone (19 kHz) into the signal in paging type
system to continually drive the speaker, allowing continuous
monitoring of the speaker load. The following controls exist:
•Sine On/Off: The sine-wave signal generator’s function.
•Sine Frequency: Controllable from 20 Hz to 20 kHz.
•Sine Level: Each channel’s sine-wave signal level can be
independently controlled.
3.2.32 Input Signal Router
Each channel of the module’s signal processing has an Input
Signal Router that lets you choose the audio signal that will be
used by the channel. Choose one of the following configurations:
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CobraNet Audio: Assign this in the CobraNet Input section of
the software. See Section 3.3.2 for more details. Choices for the
CobraNet Input are from any of four bundles, and any of the eight
channels available.
CobraNet with Analog Backup: In this mode, if CobraNet
audio is lost, the module automatically switches to the chosen
Balanced Audio Input until CobraNet audio returns.
CobraNet with Analog Override: In this mode, if a signal
appears on the Analog Input, the module’s input signal switches
from CobraNet to the Analog Input. Then the CobraNet audio will
be routed to the channel after 10 seconds.
3.3 CobraNet
CobraNet is a licensed technology developed by Peak Audio, Inc.
consisting of proprietary communications protocol, firmware and
hardware. It allows reliable, deterministic transmission of digital
audio over a 100Base-T Fast Ethernet network. The amplifier
operates as a networked device on a CobraNet network, and
interfaces digital audio from the network to the amplifier. For a
more thorough discussion about CobraNet technology, refer to
Section 8.2 and visit Peak Audio’s CobraNet website at www.
cobranet.info.
This section describes the amplifier’s CobraNet control and
monitoring features. These features are accessed via the control
software. Please refer to the software documentation if you are
unfamiliar with the software.
3.3.1 CobraNet Module Parameters
The internal CobraNet Network Interface Module contains several
parameters for control and monitor of status of the CobraNet
network, and do not directly affect the control network. These
variables can also be controlled and monitored through the
CobraNet network using CobraCAD™ or other industry-standard
SNMP-enabled network management software. CobraCAD is
software that provides a GUI to design CobraNet networks. It can
be downloaded from www.peakaudio.com.
Conductor
The Conductor is the device in a CobraNet network that acts as
the master clock. Other devices are called “Performers.” Any
CobraNet device can be configured to operate either as Network
Conductor or a Performer.
•Active Indicator: This indicator, viewable in System Architect
software, reports the present Conductor status of the device. If the
indicator is ON, the unit is operating as the network Conductor.
When OFF, the unit is operating as a Performer.
• Priority: This parameter adjusts the priority level for
becoming the Conductor. When set to zero, the amplifier will
never function as the Conductor, and when set to 255 it will
always function as the Conductor. The higher the priority number,
the more likely unit will act as the Conductor. The Priority object
is stored in presets.
System Name
This parameter can be set to any alpha-numeric string of 30
characters or less. It communicates a unique name for the
particular device to a network. The System Name object is stored
in presets.
System Description
This parameter is configured at the factory and is read-only. The
intended use is to communicate a unique device description to a
network.
System Location
This parameter is user-settable to any alpha-numeric string of 30
characters or less. The intended use is to communicate a unique
description of the device location to a network. This object is
stored in presets.
System Contact
This parameter is user-settable to any alpha-numeric string of 30
characters or less. The intended use is to communicate the
designated contact person (in case of service or other network
issue) to the network. This object is stored in presets.
Firmware Version
This parameter is configured at the factory and is read-only. The intended
use is to communicate the presently loaded CobraNet module firmware
version to a network.
MAC Address
This parameter is configured at the factory and is read-only. The setting
defines a unique IEEE802-recognized address for use with any Ethernet
based network.
IP Address
This IP address is for the CobraNet control ONLY. It is used by SNMP
agents such as CobraNet Disco to control CobraNet specific functions.
This IP address should not be confused with the control system’s IP
address that is used to control and monitor the CobraNet module.
3.3.2 CobraNet Input Routing
CobraNet input routing includes the following controls:
CobraNet Receive Bundles
The amplifier can receive four unique CobraNet Bundles (RxA, RxB, RxC,
RxD). Each Bundle includes an “Active” indicator to indicate whether the
particular Bundle is being actively transmitted onto the network.
CobraNet Receive Channels
Each CobraNet Bundle contains up to eight digital audio channels. Each
channel is selected at its respective transmitter to contain none, 16-, 20-
or 24-bit audio sample data. A total of four or eight audio channels can be
processed by the USP/CN at any one time. Any of the eight channels on a
bundle can be can be routed to either of the four or eight processing
channel inputs on the USP/CN.
•Channel Label: Each received digital audio channel can be assigned
a user-specified label to indicate intended use, source or other
information. The label is stored in presets along with the bundle number
and receive channel information.
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3.3.3 CobraNet Output Routing
CobraNet output routing includes the following controls:
CobraNet Transmit Bundles
The amplifier can transmit up to four unique CobraNet Bundles
(TxA, TxB, TxC, TxD). Each Transmit Bundle includes the
following controls and monitor functions:
•Receiver Count: This meter reports the number of CobraNet
nodes actively receiving the Bundle being sourced to the network
by this bundle.
•Transmit Priority: This control adjusts the relative priority for
the particular transmitter. Higher numbers indicate a higher
priority. One may choose to increase the transmitter priority for an
emergency page microphone in a heavily loaded network. The
Transmit Priority object is stored in presets.
CobraNet Transmit Channels
Each CobraNet Bundle can contain up to eight unique digital
audio channels. Each channel is selected at its respective
transmitter to contain none, 16-, 20- or 24-bit audio sample data.
A total of 32 channels can be transmitted by a single USP/CN at
any one time; however, only 4 channels can be sent on up to four
Bundles. The CobraNet Transmit Channel object is stored in
presets.
Here are some features of CobraNet Transmit Channels:
•Output Amplifier Audio: By sampling the actual output
audio of the amplifier, CobraNet allows remote access and
monitoring of each amplifier channel at the output of the
amplifier! CobraNet extends the “Listen Bus” or foldback
feature found on other PIP modules to any network user, allowing
them to listen to the output of any networked amplifier from any
location on the network.
• Balanced Audio Inputs: Analog audio entering the Balanced
Audio Inputs can be converted to digital, and sent onto the
CobraNet network. This provides a very cost-effective means of
CobraNet input.
3 Operation (continued)